Observed Climate Change and the Negligible Global Effect of Greenhouse-Gas Emission Limits in the State of Texas

Observed Climate Change and the Negligible Global Effect of Greenhouse-gas Emission Limits in the State of Texas www.scienceandpublicpolicy.org [202] 288-5699 Observed Climate Change and the Negligible Global Effect of Greenhouse-gas Emission Limits in the State of Texas Annual rainfall Annual maximum temperature 2 Summary for Policy Makers ariations in climate from year to year and decade Vto decade play a greater role in the Texan climate than any long-term trends. Short-term variability will continue to dominate the climate in future. The Texas climate shows no statically significant long-term trend in mean annual temperature, rainfall, floods, droughts, heatwaves, tornadoes, or hurricanes – still less any trend that could reasonably be attributed to “global warming”. Agricultural yields in Texas will continue to increase. Record crop yields will continue to be set every couple of years. The climate is not the driving reason for the improvement: but it has not prevented it in the past and will not prevent it in the future. The climate has little impact on the health of Texas’ population. Public health measures aimed at combating the health impacts of heat waves and vector-borne diseases are more cost-effective than the many expensive and largely untested proposals for mitigating “global warming” Overwhelmingly, observational scientific evidence demonstrates that “global warming” does not have and will not have any appreciable impact on the climate of Texas. A cessation of all of Texas’s CO2 emissions would result in a climatically-irrelevant global temperature reduction by the year 2100 of less than two hundredths of a degree Celsius. A complete cessation of all anthropogenic emissions from Texas will result in a global sea-level rise savings by the year 2100 of an estimated 0.32 cm, or just over one-tenth of an inch. Again, this value is climatically irrelevant Even if the entire Western world were to close down its economies completely and revert to the Stone Age, without even the ability to light fires, the growth in emissions from China and India would replace our entire emissions in little more than a decade. In this context, any cuts in emissions from Texas would be extravagantly pointless. 3 A naturally variable climate n Texas, the largest of the contiguous United States and one of the most geographically diverse, the Iclimate varies naturally and greatly by region and season. Intense heatwaves, droughts, floods, tornadoes, and hurricanes occur. In 1979 the Texas Department of Water Resources wrote: “From the blizzards that traditionally pound the Panhandle each winter to the enduring heat that scorches vast sections of Texas later in the summer, Texas in the meteorological sense truly is the "land of contrast." Perennially the State perseveres through frequent bombardments of hail, high winds, and flash floods, often with the accompaniment of tornadoes – as well as the threat of being struck on its coastal flank by a hurricane or intense tropical cyclone. “Inevitably each year some sector of Texas suffers from the effects of a tornado strike, a blinding snowstorm, a violent hail-bearing thunderstorm, or a raging sandstorm or dust storm. In many years at least some portions of the Lone Star State experience destruction or severe damage from an untimely freeze, a debilitating drought, or a lengthy spell of excessive rains. “Assuredly, no two years weatherwise in Texas are even remotely similar, for the community that reeled one year from a capricious dry spell likely is the recipient of plenty of rain in the following year, while a not-too-distant neighboring locale that hurt from a disastrous hailstorm one Spring experiences relative calm during the following year's storm season.” Observed climate change in Texas Texas annual mean temperatures, 1895-2007 Source: National Climate Data Center. 4 Temperature ince 1998 Texas has experienced several warm years. However, since the US National Climatic SData Center first kept records 113 years ago, there has been no long-term annual or seasonal trend of temperature change in Texas, and 1900-1950 was warmer than it has been since. Even the worldwide warming caused by the exceptional 1998 El Nino Southern Oscillation had no more effect in Texas than to restore temperatures that were typical until the mid-1950s, when a 40-year period of relatively cooler weather set in. Seasonally, there has been a little warming in the spring (2007 was a record) and a little cooling in the other seasons. These changes are neither statistically significant nor abnormal. Though globally many of the last ten years were among the hottest recorded, in Texas only 4 of the 20 hottest years recorded were in the past decade. The hottest year in Texas was 1921. On the evidence, “global warming” has had little impact on annual or seasonal mean temperatures in Texas. Texas temperatures by season, winter 1895 to summer 2007 Source: National Climate Data Center. Rainfall s with temperature, so with rainfall, there has been no uptrend since records began 113 years ago. AThe average is 30 inches per year. Rainfall is variable from year to year, ranging from a low of 15 inches in 1917 to a high of 42 inches just two years later. Recent rainfall is well within normal variability. 5 Texas mean annual rainfall, 1895-2007 Source: U.S. National Climatic Data Center. Seasonal rainfall can sometimes deviate sharply from the average. For instance, there was record spring rainfall in 1957, and record summer rainfall in 2007, but almost as much summer rain fell around 1920, 1940, and 1960. The fall was wet in 1913 and 1919. The winter was wet in 1932 and 1992. These fluctuations are evidence of normal climate variability, not of manmade “global warming”. Texas rainfall by season, winter 1895 to summer 2007 Source: U.S. National Climatic Data Center. 6 Drought eries of dry years leading to drought often occur in Texas. The most severe were in the mid-1910s Sand mid-1950s. But there has been no long-term change in drought frequency or severity. A dust storm approaching Spearman, Texas, April 1935. Source: NOAA Photo Library. The Palmer drought-severity index, which balances rainfall against evaporation, confirms the absence of any trend. Instead, short-term variations reflect natural variability in rainfall: Texas Palmer drought-severity index, 1895-2007 Source: National Climatic Data Center. 7 From tree-ring patterns, Cook et al. (1999; 2004) reconstructed a 1200-year summer drought-severity index for central Texas. Alternating wet and dry periods lasting several decades have often occurred, demonstrating that droughts are normal in Texas. They do not indicate “global warming”. Central Texas summer drought-severity index, 838-2003 AD Source: National Climate Data Center. Floods ainfall in summer 2007 set a 112-year record. On several occasions that summer, many days of Rheavy rain caused widespread flooding and some damage. However, such floods are not unusual. The Flood Safety Education Project describes Texas as the state that leads the nation almost every year in flood fatalities and property damage: “Flooding from large storms has affected Texas throughout its history, causing many deaths and much economic loss and hardship. Floods occur regularly in Texas, and destructive floods occur somewhere in the State every year. Many of these floods are destructive because they often occur in areas where extreme flooding had not occurred for many years. These floods often are perceived as unexpected or even unprecedented because their peak water-surface elevations (stages) can greatly exceed those of past floods.” Guadalupe River flood at Comfort, Texas, July 13-18, 1900. Source: Flood Safety Education Project. 8 Colorado River flood at Ballinger, Texas, August 5-6, 1906, after 8in. of rain. Source: Flood Safety Education Project. San Antonio River flood, Texas, Sept. 8-19, 1921. Taylor, TX, had 2ft. of rain in 24 hours. Thrall had 32in. in 12 hours. Source: Flood Safety Education Project. 9 Colorado River flood at Wharton, Texas, June 9-15, 1935, after 18in. of rain fell in six days. Source: Flood Safety Education Project. West Clear Fork Trinity River flood, Fort Worth, May 17, 1949 after 1ft. of rain fell over Village Creek. Source: Flood Safety Education Project. 10 The heavy rain in 2007 had a benefit: much-enhanced plant growth. Over much of Texas, there was 50% more vegetation growth than usual: Texas vegetation growth anomaly, summer 2007 Source: NASA / National Geographic Tornadoes Texas is partly within “tornado alley” and ranks among the most twister-frequented states: Source: National Climatic Data Center. 11 In Texas, as in the U.S. as a whole, the recent apparent increase in tornado observations owes nothing to “global warming”. It arises because the National Weather Service uses Doppler radar more widely, there are more storm-chasers, and population density has grown. Small tornadoes that were once missed are now more often detected. The number of strong tornadoes across Texas—those less likely to have been missed previously—has declined since 1950: All tornadoes up, strong tornadoes down, 1950-2006 Source: NOAA Storm Prediction Center Though the number of severe (F3-F5) tornadoes impacting Texas is falling, the threat remains real. On May 11, 1953, a violent F5 tornado touched down 10 miles south of Waco and cut a swathe of destruction a third of a mile wide through the the heart the city, killing 114 and injuring 600. In the deadliest tornado in Texas’ history and the 10th deadliest ever to strike the U.S, more than 600 businesses, 850 homes and 2,000 cars were destroyed or severely damaged. Losses were $41 million ($300 million today). 12 Aftermath of the Waco tornado of May 11, 1953. Source: NOAA.

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